JPH023699B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing an embossing roll having a female die for continuously embossing the surface of a thermoplastic sheet.

2. Prior Art A known embossing device for continuously embossing the surface of a thermoplastic sheet consists of means for heating at least the surface of the sheet and two rolls located next to these means. The heated sheet is guided between the rolls, one of which is an embossing roll having an embossing pattern on its surface. It is not difficult to manufacture such an embossed female mold seamlessly. However, thermoplastic sheets embossed with this material look unnatural.

A similar type of method for producing female molds for producing embossed structures in the surface layer of objects is also known from DE 25 52 547 A1. In this case, the female die can have the form of a press plate that is flexible and is mounted on the smooth roll of the embossing device. A joint edge is created during this attachment.
As a result, continuous embossing is possible with this embossing device, but the embossing has discontinuous portions due to the joining edge.

From DE 21 41 613 A1, an embossing roll is known which has a silicone synthetic resin layer with a raised embossed structure on its circumferential surface. This embossed structure is manufactured artificially.
In this case, it is not difficult to manufacture the same embossed structure seamlessly. However, using this
For example, embossing made on thermoplastics looks unnatural.

Problems to be Solved by the Invention The problem to be solved by the present invention is to use an embossing roll of an apparatus for continuously embossing the surface of a thermoplastic plastic sheet having natural leather embossing, which causes discontinuity in the natural embossed structure. The object of the present invention is to provide a method that can be manufactured more easily without having to do so.

Means for Solving the Problems The problem of the present invention is to solve the above problems by: (1) casting a uniform layer of a synthetic resin made of silicone rubber on the surface of an embossed pattern made of natural leather; (2) applying and then curing or crosslinking to form an embossed matrix (female mold); and then peeling the embossed matrix from the master mold; Emboss a thermoplastic plastic sheet, (3) After embossing, cut the sheet appropriately, and join the opposite edges of the sheet together in a cylindrical shape with the embossed surface (female mold) outside, and form the female embossing. (4) forming a tube that matches the dimensions of the roll;
(5) stamping the sheet tube with endless male molds again under heat and pressure using (6) Apply a uniform layer of silicone rubber using a doctor using a doctor, and then vulcanize to create an embossed female mold. (6) Apply the silicone rubber layer to the tubular male mold. The problem is solved by a method characterized in that the layer is peeled off from the roller and glued onto the circumferential surface of the roll with the female embossed surface of the same layer facing outward.

This method overcomes the difficulties caused by the absence of a continuous natural leather surface as a model. Thus, only the embossed layer, referred to throughout this specification as the embossed matrix, can in principle be produced, for example, in the form of an elongated rectangle. When such an embossed layer is bent into a tube, discontinuities occur at both edges where they join together, which is extremely unsightly. It is impossible to create a continuous embossed pattern on a thermoplastic sheet using only a tube-shaped embossing mold.

The essence of the present invention is to overcome this difficulty of discontinuity and to make it possible to form a continuous embossed pattern in a thermoplastic sheet. To this end, the invention provides the advantage that the surface structure can be modified by embossing a thermoplastic sheet, which is likewise discontinuous, from a discontinuous embossing matrix. The intention is to create an intermediate male type with similar characteristics. According to the present invention, the discontinuity disappears when the area where the discontinuity of the male die is noticeable is again embossed with the female embossing die. During this restamping, the thermoplastic sheet gains the necessary temperature for welding in the region of the two edges that join together, so that the joining edges are welded together at the same time.

Since the re-embossment is circumferentially limited, there is a transition where the re-embossed structure passes into the structure that was originally embossed in the embossing mold. However, this transition is so continuous that it is virtually no longer observable in practice.

Embossing thermoplastic sheets with embossing molds can be easily carried out using a flachpress, but in principle it is not impossible to embossing thermoplastic sheets using a roller press. Re-embossment of the thermoplastic sheet sheet using the same embossing mold can also be carried out in a step press, but in this case the press is elongated so that re-embossment occurs only in the joining area.

The thickness of the embossed female mold obtained by applying the silicone rubber layer using a doctor is extremely uniform, and the application using a doctor is designed to ensure that the silicone rubber is well pressed into the holes of the male mold.

Instead of a natural leather surface, any other type of surface structure can also be used as a prototype, for example woven, nonwoven, wood surfaces, etc.

Example 1 In order to manufacture an embossing roll for continuous embossing of a thermoplastic sheet, first a pattern made of natural leather was stretched on a surface support layer.
Secure the edges. A frame-like border is provided around the edges to form a casting mold into which the non-adhesive silicone rubber is poured. The silicone rubber precisely conforms to the minute ridges on the surface of the original,
It also enters the pores and even surrounds the hair. The silicone rubber is then vulcanized, gelled or solidified, and peeled from the master. This process is repeated several times to produce several embossed molds. These molds each have a thickness of 3 to 4 mm and are bonded to each other on the back side by adhesive tape.

The formed body produced in this way, consisting of several embossed molds, is placed in a corrugated press together with a thermoplastic sheet having a thickness of approximately 0.8 mm. In this case, the thermoplastic sheet lies below and above it there is an embossed sheet with an embossed surface facing downwards.

Now, the thermoplastic sheet is heated directly from below to about 190°C, and then heated to the same temperature from above using an embossing mold to plasticize it. Due to the simultaneously applied pressure, after a certain time an exact replica of the structure of the embossed matrix is obtained on a thermoplastic, for example made of polyvinyl chloride. It is then cooled and the embossed thermoplastic sheet is removed.

This thermoplastic sheet is cut to an appropriate size according to the width and circumference of the embossing roll, and then bent into a cylindrical shape to form a tube. The embossed or embossed surface is on the outside. At this time, carefully align the joints and connect them with adhesive tape from the back side. Next, only the joint portion of the tube is placed in a long and narrow step press, and an embossing matrix is placed on the joint portion within the same press. Heat and pressure are then applied to effect the desired re-embossment in the area of the joint. At the same time, the mutually joining edges are welded.

The thus produced tube having a male mold with an embossed structure on the outside is mounted on a roll, and the roll is placed in a stand having bearings and rotated continuously. Next, a uniform layer of silicone rubber is applied using a doctor and the rubber is then vulcanized. The rotation of the rolls is maintained during these strokes, and uneven layer thicknesses are avoided.

The silicone rubber tube manufactured in this way is
Peel off and fold back after vulcanization. On the outer surface there are patterns, skin, fibers, etc. taken from the original mold as a female mold. After pre-coating the roll surface with fixer and silicone adhesive, the tube is stretched onto the roll. After curing of the adhesive layer, the roll can be used as an embossing roll in a continuous embossing device for thermoplastic sheets.

Claims (1)

[Claims] 1. A method for manufacturing an embossing roll having a female mold for continuously embossing the surface of a thermoplastic plastic sheet, which includes: casting or coating a synthetic resin as a uniform layer, then curing or crosslinking to form an embossed matrix (female mold), and then peeling the embossed matrix from the master mold, (2 ) Emboss a thermoplastic sheet under heat and pressure using the embossing matrix, (3) Cut the sheet appropriately after embossing, and place the sheet facing each other with the embossed surface (female mold) outside. cylindrically joining the edges to each other to form a tube that matches the dimensions of the female embossing roll; (4) connecting the joining area of the tube to the embossing master (female mold);
(5) stamping the sheet tube with endless male molds again under heat and pressure using (6) Apply a uniform layer of silicone rubber using a doctor using a doctor, and then vulcanize to create an embossed female mold. (6) Apply the silicone rubber layer to the tubular male mold. An embossing roll having a female mold for continuously embossing the surface of a thermoplastic sheet, characterized in that the embossing roll is peeled from the same layer and adhered onto the circumferential surface of the roll with the female embossing surface of the same layer facing outward. Production method. 2. The method according to claim 1, wherein the thermoplastic sheet is embossed with a step press using an embossing mold. 3. Re-embossing the thermoplastic sheet,
2. The method of claim 1, wherein the method is carried out in an elongated, generally flat step press using an embossing matrix.